Track Spacing

[KJM]

Hi All

 

Could somebody let me know in millimeters the track center to track centre of parallel peco oo gauge track, (is this what they call the six foot..)

 

Regards

[loickebros]

Just buy one of these http://durhamtrainsofstanley.co.uk/my_store/index.php?main_page=product_info&cPath=119_120_52&products_id=4890

Dave

[Kris]

The 6ft is the gap between 2 mainline tracks rather than track centre to track centre. It's also not a fixed distance, with some examples of distances that are less than this (not a normal situation) but many examples that are greater distance. The minimum distances between running lines and sidings is generally considered to be 10ft (40mm). Theoretically 6ft in OO is 24mm but (from memory) if you use Peco pointwork the gap is greater than this to allow for the small radius curves the we modellers are forced to use.

 

If you look at this link to Peco you can download and print the point plans from which you will be able to see the gap between the tracks caused by Peco pointwork.

[edcayton]

The Peco gadget has two spacers-one for their setrack and one that fits with Streamline geometry. Remember, the tighter your curve radii the more clearance you will need. If you use the smaller spacer then you will have problems on sharp curves.

 

What I don't know, and hopefully someone here will, is the minimum radius you can go to using the smaller spacer. It will also depend on the stock you use eg Mk3 and Mk4 coaches, modern freight stock and big loco's.

 

Really, you need to experiment BEFORE you fix any track down. This can be fun!

 

Ed

[KJM]

Thank you all for the advice, I am using SMP track and large peco points, so maybe I should just go and buy the peco spacer.

 

Regards

[craigwelsh]

The 6ft is the gap between 2 mainline tracks rather than track centre to track centre. It's also not a fixed distance, with some examples of distances that are less than this (not a normal situation) but many examples that are greater distance. The minimum distances between running lines and sidings is generally considered to be 10ft (40mm). Theoretically 6ft in OO is 24mm but (from memory) if you use Peco pointwork the gap is greater than this to allow for the small radius curves the we modellers are forced to use.

Its also got to be wider than prototype as the rails are too close together in 00 giving vehicles a larger overhang from the track.

[Karhedron]

I believe that 2 Peco streamline points arranged in a cross-over will give a centre-to-centre distance of 50mm in 00. This equates to 12.5' or a distance between adjacent rails of 8'. This means it is about 33% overscale as others have mentioned.

[The Stationmaster]

I believe that 2 Peco streamline points arranged in a cross-over will give a centre-to-centre distance of 50mm in 00. This equates to 12.5' or a distance between adjacent rails of 8'. This means it is about 33% overscale as others have mentioned.

 

This is an area where I have always thought 'someone' brought in an extra distortion in already well distorted 00 dimensions. The prototype minimum for running line track centres is 10ft 8.5" and I can't see any reason to not use that on straight track in 00 although obviously there has to be widening on curves. And taking that approach would at least help to reduce the 'narrow' appearance of 00 track.

However with set-track type systems changing the 6ft interval on curvature means the 'outer' track has to curve later than the inner so throwing out lots of easy geometry. So presumably someone decided starting curves from a parallel location was simpler and preferred and therefore went for greater distortion than necessary?

 

[melmerby]

This is an area where I have always thought 'someone' brought in an extra distortion in already well distorted 00 dimensions. The prototype minimum for running line track centres is 10ft 8.5" and I can't see any reason to not use that on straight track in 00 although obviously there has to be widening on curves. And taking that approach would at least help to reduce the 'narrow' appearance of 00 track.

However with set-track type systems changing the 6ft interval on curvature means the 'outer' track has to curve later than the inner so throwing out lots of easy geometry. So presumably someone decided starting curves from a parallel location was simpler and preferred and therefore went for greater distortion than necessary?

 

But if you are modelling an ex Broad Gauge GWR line the Peco-size gap would be near prototypical in many cases.

Look at the difference in track centres on the 4 track line from Paddington. The two later original standard gauge tracks have closer spacing than the two ex broad gauge tracks in many locations.

 

Keith

[naugytrax]

To answer the OP's actual question, the Peco "Six-foot way gauge", SL-36, gives spacings of 50.0 mm on the Streamline side and 66.5 mm on the Setrack side.

 

I use the Streamline spacing on straight track. My minimum radius is 24 inches, with easements, and my longest vehicles are Hawksworth coaches, 10.5 inches over buffers. As the track eases into the curves, I eased the spacing out to 60.0 mm at the tightest radius. It turned out that this provides about 13 mm clearance between GWR Centenary coaches, which are my widest stock, and about the same between BR Mk I coaches, which are longer but narrower. So it's possible that I didn't need to increase the spacing on curves at all, but I wanted to leave plenty of space for visitors with longer coaches, and to allow for possible inaccuracy in my track-laying. Probably about 55 mm spacing would give a better appearance on 24 inch curves. (If appearance can be said to be a priority on this ridiculous curvature!)

[Poor Old Bruce]

The prototype minimum for running line track centres is 10ft 8.5"

Sorry SM, you usually talk a lot of good sense but I think you have your sums wrong here. I assume your 10ft 8.5in is made up of 4ft 8.5in track gauge (ignoring the fact that some bright spark change it to 4ft 8.375in at some stage for CWR and totally cocked up vehicle riding) plus the 'six foot' between the tracks. We all know that the track gauge is measured between the inside edges for the rails for the 4ft 8.5in but the 'six foot' is measured between the OUTSIDE edges of the rails, so for normal minimum track centres you need to add two rail head widths of 2.75in each making the centres 11ft 2in.

[TheSignalEngineer]

Three items to note.

 

1 - Where there are more than 2 tracks, at least one of the intervals should be a 10 foot way. The GWR were quite lucky on this as they kept the old Broad Gauge interval in a lot of places when extra tracks were laid on either side.

 

2 - In 00 the track gauge is only 4' 1.5". Given that the stock is the same width as on 4' 8.5" gauge on the 1:1 railway, the 6 foot needs to be slightly wider. Using track centres is a more reliable way of avoiding side-swipes.

 

3 - Don't forget that because of non-prototypical curves there is extra side and end throw, particularly on bogie vehicles and locos. The minimum Passing Clearance between vehicles should be 18 inches at 1:1 or 6mm in 00.

[The Stationmaster]

Sorry SM, you usually talk a lot of good sense but I think you have your sums wrong here. I assume your 10ft 8.5in is made up of 4ft 8.5in track gauge (ignoring the fact that some bright spark change it to 4ft 8.375in at some stage for CWR and totally cocked up vehicle riding) plus the 'six foot' between the tracks. We all know that the track gauge is measured between the inside edges for the rails for the 4ft 8.5in but the 'six foot' is measured between the OUTSIDE edges of the rails, so for normal minimum track centres you need to add two rail head widths of 2.75in each making the centres 11ft 2in.

 

 

 

Bruce you're absolutely right (can I add 'twice'). I looked at the diagram far too quickly and I should indeed have added the width of the two railheads to bring the centres to 11ft 2ins - thanks for correcting me.

[Pete the Elaner]

1 - Where there are more than 2 tracks, at least one of the intervals should be a 10 foot way. The GWR were quite lucky on this as they kept the old Broad Gauge interval in a lot of places when extra tracks were laid on either side.

 

I read this a few weeks ago so have been paying attention to it on my daily commute. It may be a principle but is not adhered to universally. It is not true of most of the southern 4-track section of the WCML. Other than at stations & tunnels, the 4 tracks are spaced more or less evenly.

 

I think on straight sections, you can make a huge improvement by moving the lines 5mm closer without causing trouble. I will try this on some test track before starting on my next layout.

[Gwiwer]

The minimum Passing Clearance between vehicles should be 18 inches at 1:1 or 6mm in 00.

 

"Should be" being the operative words here. That's fine on straight track (though with the Peco geometry overscale as others have noted) but we do need to compensate for our distinctly tramway-radius curves. Being lucky enough to have a lot of space I have also endeavoured, where possible, to use flexitrack to advantage creating entry and exit curves rather than a sudden jerk from straight to maximum curvature. Straight track was laid using the Peco gauge which worked perfectly. With the tightest curve on my layout slightly more generous than Setrack's largest radius I checked before it was pinned down with several different vehicles for throw and overhang.

 

Mk 3 passenger coaches overhang significantly at the centres but I found a surprise in that the Heljan Cargowaggons seem to have the largest over all "kinematic window" as it was these which ultimately dictated track spacing.

 

On the tighter curves I have vehicle ends passing as close as 2mm where to adhere to the 6mm rule would result in the tracks being an uncomfortable distance apart. Through the fiddle yard, where space is at a premium and the most number of tracks must be squeezed in, parallel straight tracks are laid with stock no more than 1.5mm apart in most cases. Those are not laid using the gauge but by fixing one reference track and placing the stock onto it, then placing stock on the next (unfixed) track to check clearance before pinning it down. That way I got seven tracks into the space of six and for viewing purposes it matters not a jot.

[TheSignalEngineer]

I read this a few weeks ago so have been paying attention to it on my daily commute. It may be a principle but is not adhered to universally. It is not true of most of the southern 4-track section of the WCML. Other than at stations & tunnels, the 4 tracks are spaced more or less evenly.

 

I think on straight sections, you can make a huge improvement by moving the lines 5mm closer without causing trouble. I will try this on some test track before starting on my next layout.

 

Standards are a moving feast. At the time when most of the southern end of the WCML was 4-tracked it looks to have been done on the basis of minimum land take and minimum widening of cuttings and embaknments. When I worked on it I found a few places where the six-foot wasn't even six feet wide in those days, let alone providing a ten-foot.

[TheSignalEngineer]

"Should be" being the operative words here. .

 

All layouts have an element of compromise. Viewing angles in the 1:1 world are considerably different from those for models, so it is a often matter of getting something that looks right rather than being 100% dimensionally accurate.

[Guest Redskalie]

Hi

 

I know this is an old thread but it was the only one I could find on the subject.

 

I am using Peco Streamline 100 in all cases and considering the streamline spacing for straights, but as a buyer rather than a model maker, I tend to buy things like footbridges and level crossings.

 

So how best to handle these as they are designed for set track spacing.?

 

Do you widen from streamline to set track to accommodate stations and level crossings or run set track widths everywhere?

[Gwiwer]

I would stick with Streamline spacing and adapt the structures where possible.

 

If you have Streamline spacing and then widen that to fit structures (and reduce it beyond the structure) your end result may look strange indeed.

[Kris]

Not all are designed for set track spacing. Many very easy to build level crossings will be set for a different width. As to the foot bridges these could simply come down further from the track.

[Guest Redskalie]

Cool

 

I will keep an eye out for appropriate items

 

Thanks both of you for your replies.

[steves17]

So just a quick fire answer for 1in76 scale strait track representing a main line section, would 4.5cm between the track centres be correct or is this a shade under par? I'm pretty sure I recall that Norman Solomon mentions that on the Right Track DVD but putting it against a diagram I have it seems a shade narrow (whether it's correct or not I suspect the 4mm scale LMS diagram I have is wider than the general standard).

Also in cm/mm what would be a typical (non ex-broad gauge legacy) minimum distance between a main line track and a siding?

 

Thanks

Steve 

Edited May 17, 2017 by steves17

[DCB]

There are several threads on here about track spacing

I use the least clearance I can get away with as my double line curves range from 15" to 60" radius. 

The crucial dimensions are the width of your stock, GWR Centenaries at  9ft 7" or 38.5 mm is the widest I know of but the Airfix models don't look anywhere near that while some ex Triang stock is seriously over width.  Given 1/2 X 38.5 X 2 is the space between the centre lines of two tracks taken up by trains plus 18" or 6 mm minimum clearance between trains then a spacing of around 44.5mm sounds about right.   This means carving moderate size lumps off Peco streamline points for crossovers and massive chunks off Set Track.

Given that I get down to 42mm in sidings,   However if you want to stick at 52mm streamline spacing why not put some junk between tracks, Bridge girders are a handy subterfuge as under bridges, especially river bridges are greatly under represented on models,

Prototype tracks don't keep to a set 6 foot way slavishly, they tend to weave around obstacles so I aim to narrow them down between platforms, but remember set track spacing is there to allow pudgy little fingers to slip between tracks to rerail coaches and if you go 42 or 44mm a derailment will drag the adjacent train along or off the rails.

In most cases tracks are paired and a larger gap, the "10 foot" provided between tracks adjoining the pairs, sometimes you get 4 track lines paired 1+2 and 3+4 but equally it can be 1 - 2+3 -4, likewise a 10 foot was a good minimum between sidings and running lines.   

Its about what looks right.   Don't stick to a set figure widen it on curves and narrow it between straight platforms.   I hope a few pics are attached showing what the prototype looks like .

 

Edited May 18, 2017 by DavidCBroad

[Trog]

4ft 8.5in track gauge (ignoring the fact that some bright spark change it to 4ft 8.375in at some stage for CWR and totally cocked up vehicle riding).

 

A little late in replying but the gauge was changed back to 4'-8 1/2" 1435mm in the mid 1980's, and the current G44 CEN60 track used on mainlines since 1999 is 4'-8 39/64" 1438mm.

 

As for the more recent question about sidings adjacent to running lines 10' between outside edges was standard for many years, although as said above using the equivalent centreline dimension might be a good idea. Very old layouts may have sidings at closer spacing's and new layouts are likely to be wider. 

[ejstubbs]

Also in cm/mm what would be a typical (non ex-broad gauge legacy) minimum distance between a main line track and a siding?

 

I've read that the minimum distance between a siding and a running line was 15'2" between track centres ie "the 10ft" rather than "the 6ft".  That would be 61mm, to the nearest mm.  This thread is one of many which has a useful discussions about siding spacings.

 

Between parallel running lines it was 11'2", which is indeed 45mm in 4mm scale (44.67mm if you want to be more picky).

 

As David says, there are many other threads on RMWeb about track spacing.

 

(I know I sometimes bang on about people using the search facility, but is it just me that finds it a little irking when someone resurrects a long-dead thread to ask a single question, often only peripherally related to the OP?  It pops up looking like a new thread, and you realise after a while that you're wading through stuff that was discussed years ago - and sometimes containing information which has since been superseded - only to find at the end a single post asking a question that you know is answered, or at least adequately discussed, in other more recent threads - or even higher up the same thread.  Oh, OK, it is just me.  I'll shut up, then.  As you were.)

Edited May 18, 2017 by ejstubbs